Typically trailer frames are manufactured by welding frame members together. Typical frame members include I-beam, flat, L-shape, U-shape or tubular rail sections. The frames generally have a ladder construction with axle units connected to the side frame members of the ladder near the center or rearward portion of the frame. These trailer frames are used for boat trailers, car trailers, recreational vehicles, horse trailers, utility trailers, and the like.
Since the entire frame, including the axle is pre-assembled, shipping may be difficult with only a few assembled frames being shipped at any time. In most cases, frames are built on a made to order basis to avoid maintaining pre-assembled frames in inventory.
It is desirable to have camber within the frame typically at the rearward end of the frame to accommodate loads placed on the frame. When loaded, the frame will deform. To level the load on the frame, existing manufacturers heat the frame to cause it to deform and create camber. Existing frames are ladder frames having a pair of I-beams that extend the length of the frame. To create positive camber at the rear of such a frame, for example, a weld is placed along the top side of the frame members between the axles and the rear end of the frame to draw the rear end up. Once positive camber is created, water is thrown onto the weld to rapidly cool it and lock the camber in place. Since relying on the heat of the weld to create camber is imprecise, additional welding may be used to adjust the camber to a suitable amount. This method of creating camber alters the material properties of the metal at the weld and may make the frame more susceptible to failure. Alternatively, the frame members may be pounded or otherwise mechanically deformed to achieve the desired camber. It will be appreciated that the variables involved in either method prevent any consistency in the amount of camber achieved for each trailer frame.